JPS59232989A - Device for producing single crystal of compound semiconductor - Google Patents

Abstract

PURPOSE:To detect exactly the shape of a pulled up single crystal and the position of a melt surface and to obtain the crystal having high quality with high performance by irradiating an X-ray to the single crystal formed by a pull-up method and the neighborhood of the melt surface, moving the irradiating position and detecting the presence or absence of the diffracted beam. CONSTITUTION:The X-ray irradiated from a movable X-ray source 2 alongside a furnace 1 for pulling up a single crystal passes through the outside wall of the furnace body 1, a heater 7 and a crucible 6 and irradiates a pulled up single crystal 4 and the neighborhood of a melt surface 5. The single crystal of a compd. semiconductor is generally pulled up by determining the pull-up face to, for example, the direction <100> and therefore the face regulated by said direction appears on the side face of the crystal 4. If the X-ray having a wavelength lambda is irradiated to such single crystal from the side thereof, a diffracted beam is generated in the position deviated by an angle theta relative with the direction where the X-ray is irradiated. Since such generation occurs in the crystal face appearing on the side face of the single crystal, the irradiating position of the X-ray is moved and the presence or absence of the diffracted beam is detected by an X-ray detecting part 3 turnable around the furnace 1, by which the outside shape of the crystal 4 and the position of the surface 5 are known.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an apparatus for producing a single crystal, and more particularly to an apparatus for producing a compound semiconductor single crystal using a pulling method.

To produce a single crystal such as GaAs by the pulling method,
It is important to control the pulling speed so that the diameter of the single crystal increases and to monitor the position of the melt surface. Direct detection was difficult.

In such cases, indirect detection methods have been used, such as measuring the weight of the single crystal or observing the left TV camera from diagonally above. That is, the current situation is that it is not possible to accurately detect the diameter of a single crystal, and that detection of the state of the melt surface has not yet been realized.

In order to improve this problem, an attempt was made to find out the crystal shape by X-ray transmission method. However, this method utilizes the difference in X-ray transmittance between GaAs, the heater furnace material, and the molten material in the elemental order, and although it is possible to detect the shape of a single crystal, the X-ray transmittance of GaAs crystal and its melt is Since the transmittance is the same, it has the disadvantage that it is essentially difficult to know the melt surface position.

An object of the present invention is to eliminate the drawbacks of the above-mentioned prior art and provide an apparatus for manufacturing a compound semiconductor single crystal that can accurately determine the diameter dimension of the single crystal and the position of the melt surface. has an X d source that is movably installed on the side of the single crystal pulling furnace, and an X-ray detector that is rotatably installed around the single crystal pulling furnace at a position different from the X ray source. Then, the X-ray irradiation position from the X-ray source is scanned to detect the shape of the single crystal and the position of the melt surface, and the presence or absence of the X-ray diffraction beam is detected to determine the shape and crystallographic properties of the single crystal. The reason lies in the fact that it is configured in such a way that it can be controlled.

FIG. 1 is a plan view of a compound semiconductor manufacturing apparatus according to an embodiment of the present invention, and FIG. 2 is a sectional view taken along line AB of the apparatus shown in FIG. 1 is a pulling furnace main body, 2 is an X-ray source, 3 is an X-ray detector, 4 is a pulled single crystal, 5 is a composition melt surface, 6 is a crucible, 7 is a cylindrical heater, 8 is a single crystal pulling shaft , 9 is the rotator of 8.

That is, the X-rays emitted from the X-ray source 2 pass through the outer wall of the pulling furnace main body 1, the heater 7, and the crucible 6, and pass through the pulled single crystal 4.
, irradiates the vicinity of the melt surface 5.

In general, compound semiconductor single crystals are pulled, for example (10
Since we are pulling up in a direction such as 0>,
The side surface of the pulled single crystal 4 has a plane C defined by this.
In the cubic system, (110) and (100) planes appear. When such a single crystal is irradiated with X-rays of wavelength λ from the side, a diffracted beam is generated at a position deflected by an angle θ with respect to the direction of X-ray irradiation. This diffracted beam is due to crystal planes appearing on the side surfaces of the single crystal. Therefore, X
By moving the ray irradiation position and detecting the presence or absence of the diffracted beam, the outer shape of the pulled single crystal 4 and the position of the melt surface 5 can be determined. Note that since the X-ray source 2 is movable vertically and horizontally, the detection operation is performed while scanning the X-ray source 2.

Furthermore, an example of pulling a GaAs single crystal will be described next.

(1) The Xa source 2 is placed on the side of the pulling furnace main body 1 as shown in Fig. 1, and the single crystal 4 is pulled by electromagnetic scanning of the X-ray beam or by mechanical movement of the X-ray source 2 vertically and horizontally. Adjust so that the X-rays can hit the vicinity of the melt surface 5 well.

(2) GaAs is generally pulled in the (100) direction, and it is still common to pull and grow the pulled single crystal while rotating it. There are four (100) planes and (11) planes on the sides of the crystal.
0) The face appears twice. Therefore, when the pulled single crystal 4 is irradiated with X-rays of wavelength λ from the side, if the interplanar spacing of the <ioo> plane is d and the interplanar spacing of the <110) plane is d, then 2 d 1s stone θ 1'' ” fL λ2d2s stone θ
2°n λ However, strong diffracted beams are generated at angles 2θ1 and 2θ2 that satisfy the formula n is an integer, and no diffracted beams are generated from a space where the single crystal does not exist or from a melt portion.

(Direction) As mentioned above, during one rotation of the pulled single crystal 4, the single crystal emits 2θ four times in the direction of 2θ1.

Since a diffracted beam is generated periodically twice in each direction, the X-ray detection section 6 is arranged in that direction.

Then, by scanning the space including the single crystal and the melt surface with X-rays, the shape of the single crystal and the position of the melt surface 5 can be determined from the presence or absence of the diffracted beam and geometric information about the absorption of the X-rays.

Note that when seeding a single crystal, if the above-mentioned operation is sometimes performed, information regarding the crystal growth direction, the presence or absence of twin (twin) generation, and the presence or absence of polycrystalization can be obtained.

The compound semiconductor single crystal manufacturing device of this example enables control of the diameter of the single crystal and the position of the melt surface, producing high-quality crystals with low dislocations, as well as producing large-diameter single crystals. Sexuality improves. However, with seeding, not only the external appearance but also crystallographic knowledge can be obtained regarding the state of crystal growth at the time, so seeding can be carried out under optimal conditions.

The compound semiconductor single crystal manufacturing apparatus of the present invention has the advantage that high quality crystals can be obtained with high efficiency because the position of the melt surface and the dimensions and characteristics of the pulled single crystal can be accurately determined.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a plan view of a compound semiconductor manufacturing apparatus according to an embodiment of the present invention, and FIG. 2 is a sectional view taken along line AB of the apparatus shown in FIG. 1; Pulling furnace main body, 2; X-ray source, 6; X-ray detection section, 4;
Pulled single crystal, 5; melt surface, 6; crucible, 7; heater, 8; single crystal pulling shaft, 9; Luppo rotator. 7- Death 1 Figure

Claims (1)

[Claims] (1) An X-ray source is movably installed on the side of the single-crystal pulling furnace, and an X-ray detector is installed at a position different from the X-ray source and is rotatable around the single-crystal pulling furnace. Has the above X
The shape of the single crystal and the position of the melt surface are detected by scanning the X-ray irradiation position from the radiation source, and the presence or absence of the X-ray diffraction beam is detected to control the shape and crystallographic properties of the single crystal. 1. A compound semiconductor crystal manufacturing apparatus characterized by being configured as follows.